Gas washing



I Aug; 4, 1936.

G. H. C. CORNER ET AL .GAS WASHING Filed April 14, 1932 3 Sheets-Sheet 3FIG. 3

W E & /7(5/)7/7.

Patented Aug. 4, 1936 UNITED STATES PATENT OFFICE GAS WA George HenryClifford McGinn, Birmingham, Imperial Chemical Ind SHING Corner andJoseph England, assignors to ustries Limited, a. cor- In Great Britain 1Claim.

This invention relates to the removal of dust and sulphur compounds fromfiue gases, especially the gases from pulverized fuel boiler plants, bywashing.

According to the invention, in apparatus of the type in which such gasis passed transversely in contact with continuous films of water flowingdown the surfaces of vertical baffles, improved efficiency of dust andsulphur compound removal is obtained by providing two or more successivesets of interpenetrating curved baflles, in the line of gas flow, insuch a manner that the gas follows a sinuous course in contact with thefilms of water flowing down the concave surfaces of the bafiles, withoutincurring any sharp changes of direction. The term set" as used hereinin relation to baflle plates means a number of battle plates arrangedside by side across the line oi' gas flow. Preferably the curvature ofthe bafllcs is increased in successive sets in the direction of gas flowso as to cause the gas to be subjected to progressively intensercentrifugal force as the purification procecds, thus distributing thepurificaticn more evenly among the several sets of baflles. If desired,the curvature of the baflles in the final set or sets may be reduced soas to reduce the local gas Velocity and avoid entrainment, of water, thecarrying over of which into the exit duet is undesirable.

Figures 1 and 2 of the accompanying drawings illustrate, in plan, twoarrangements of bafile plates in accordance with the invention. Fig. 3is a vertical section on the line 3-3 of Fig. l.

In Figure 1, twelve sets of curved vertical baffle plates are providedwith four plates in each set. The plates in each set are spaced 9"apart, this distance being measured along the axis of symmetry of thefour plates in each set. The reference numerals 2, 2a, 2b, and 20 denoteone set of battles, and the numerals 3, 3a, 3b, and 3e one of theneighbouring sets of bailles. It will be seen that the plates inneighbouring sets are curved in opposite directions and are staggercd,so that corresponding plates of like curvature in alternate sets arebrought edge to edge. The curvature of the bafiles is increased from thefirst set ll in successive sets in the line of gas flow so that thebattles 2, 2a, 2b, and 2e in the central set are approximatelysemi-circular, the curvature being diminished towards the outlet in thecase of the sueceeding sets 3, 4, 5, 6 and l.

The structure shown in Figure 2 diflers from that of Figure 1 in thatthe sets of baffies are progressively spaced further apart in the lineof gas flow. The object of this arrangement is April 14, 1931 to allowthe gases from which most of the dust has been removed to leakto theback or convex surfaces of the baffles. In passing any one bafiie thesolid and liquid particles will be thrown nearcr to the concave surfaceowing to the action of 5 the centrifugal force, and-the layers of gasfurther from the surface will consequently contain a smaller proportionof suspended matter. By the arrangement shown, progressively greaterquantities of the gas from which the bulk of 10 the suspended' matterhas been removed are allowed to b'y-pass the concave baflie surfaces. Inthis way the total gas resistance of the apparatus is reduced.

Thus, as shown in Figure 2, the axes of sym- 15 metry 'of the sets ofbattles 8 and 9 are spaced apart a substantially greater distance thanthe corresponding sets of baffles in Figure 1. In Figure 2, the axes ofsymmetry of sets of battles 8 and 9 are so spaced that the proximateends 20 of these bafiles interpenetrate battles i3 near the surfacethereof and more remote from the centers than do the correspondingelements in Figure 1. However, the axes of symmetry of bafiles 8,

9, IO, II and i2 progressively approach each other 25 in the order givenas do the axes of symmetry in sets of baflles l3, i4, i5, i6 and ll.

In Figure 3 the four baffles bisected by the section line 3-3 in Figure1 are indicated by numerals 3. The portions 3' are the concave por- 30tions of the same baiiles seen in elevation, and 2' are the convexportions of the bafiles of the next set also in' elevation. The bafflesare bent at the top as shown in order to catch the water, which issupplied from a perforatecl pipe 8 and 35 falls on to a gridwork 9,which distribute it evenly partly over the concave surfaces of thebafiles and partly over the convex surfaces.

The baflies may also be arranged in such a manner that the total widthof successive sets across 40 the line of gas flow diminishes, the casingin which the baflles are mounted being correspondlngly tapered, thuscompensating the gas Velocity which wouldotherwise fall as the gasescooled during their passage through the apparatus. The 4 casing has oneside open to provide an inlet for the gas and has an opening in theopposite side to provide an outlet. The inlet temperature of the gasesmay be 200 C., for example, and the exit temperature C.

The baiiles may be irrigated with water, hot or cold, or with othersuitable washing medium such as dilutc alkaline solutions, e. g. limewater or milk of lime, also either hot or cold. The washing medium maybe fed to the baflles from 55 overhead sprays or an overhead gridwork orWe are aware that in apparatus for cleaning -air and for removing solidor liquid matter from gases by washing, the gas has been passed throughsinuous channels formed by parallel corrugated bafiles or by arranging anumber of plates or curved baffles edge to edge, but the distinctivefeature of the present invention is that the baflles of neighbouringsets interpenetrate, i. e. they are arranged so that the gas is sweptdirectly from the concave surface of each baffle of one set to theconcave surface of the next baflle of the adjacent set.

As many apparently widely different embodlments 'of this invention maybe`made without departing from the spirit and scope thereof, it is to beunderstood that we do not limit ourselves to the specific embodimentsthereof except as defined in the appended claim.

We claim:-

An apparatus for the removal of dust and sulphur compounds from fluegases by washing, comprising a casing containing a number of verticalbales arranged in a plurality of sets in the line`of gas flow andadapted to cause the gas under treatment to follow a sinuous coursewithout incurring any sharp change of direction, means for causingcontinuous films of water to fiow down the surfaces of said bafiles,said casing having one side open to form a gas inlet while the oppositeside is open to provide a gas outlet so arranged that the gas undertreatment fiows transversely in contact with said films of water, saidbattles having a concave and a convex surface and being so placed that aprogressively increasing proportion of gas is allowed to flow over theconvex sides of the balfles while the remainder of the gas is sweptdirectly from the concave surface of each baffle to the concave surfaceof a battle in the succeeding set.

GEORGE H. C. CORNER. JOSEPH MCGINN.

